(1) Field of the Invention
This invention relates to the structure of bond pads using the via plug process and more specifically to bond pads using three metal pad layers with via plugs between the first and second metal pad layers and between the second and third metal pad layers.
(2) Description of the Related Art
When an integrated circuit element has been completed electrical connections must be made to the next level of integration after the integrated circuit element. Bond pads provide a location for bonding wires or other connectors for this purpose. It is important that the bond pad structure be reliable and provide a reliable bond or the integrated circuit element will become useless.
A bond pad structure is shown in U.S. Pat. No. 5,266,522 to DiGiacomo et al. using metallurgy chosen to minimize corrosion and stress in the bond. U.S. Pat. No. 5,403,777 to Bryant et al. describes a bond pad using a barrier layer followed by two conducting layers to form a bond pad with good adhesion.
This invention provides a bond pad using three layers of metal pads with via plugs between the layers and is different than the bond pads described by DiGiacomo et al. or Bryant et al.